Zeng Li, Sun Hongjuan, Peng Tongjiang
School of Architecture and Civil Engineering, Chengdu University, Chengdu, China.
Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, China.
Front Chem. 2022 Mar 17;10:839680. doi: 10.3389/fchem.2022.839680. eCollection 2022.
The direct sintering process of coal fly ash for the preparation of glass-ceramics is the liquid-phase sintering process, from non-densification to densification. When the temperature exceeds the densification temperature point, the porosity of glass-ceramics on the contrary increases and the pore diameter increases. This provides a basis to prepare porous glass-ceramics by direct overfiring. Adding borax to coal fly ash can reduce the temperature of liquid phase formation, reduce the preparing temperature of porous glass-ceramics, achieve the purpose of energy saving. The effects of borax on the structure, properties and sintering kinetics of porous glass-ceramics prepared from coal fly ash by overfiring were investigated. It is found that the introduction of B-O bond can change the network structure of non-crystalline vitreous in coal fly ash, reduce the melting temperature, promote the formation of liquid phase, and thus increase the porosity of porous glass-ceramics. This paper provides a certain experimental basis for the preparation of porous glass-ceramics by direct overfiring of coal fly ash at low temperature without adding pore-forming agent, and provides a new possibility for the high-value resource utilization of coal fly ash.
用于制备玻璃陶瓷的粉煤灰直接烧结过程是从非致密化到致密化的液相烧结过程。当温度超过致密化温度点时，玻璃陶瓷的孔隙率反而增加且孔径增大。这为通过直接过烧制备多孔玻璃陶瓷提供了依据。向粉煤灰中添加硼砂可降低液相形成温度，降低多孔玻璃陶瓷的制备温度，达到节能目的。研究了硼砂对过烧粉煤灰制备的多孔玻璃陶瓷的结构、性能及烧结动力学的影响。发现B-O键的引入可改变粉煤灰中非晶态玻璃体的网络结构，降低熔融温度，促进液相形成，从而增加多孔玻璃陶瓷的孔隙率。本文为低温下不添加造孔剂直接过烧粉煤灰制备多孔玻璃陶瓷提供了一定的实验依据，为粉煤灰的高值资源化利用提供了新的可能性。
